tutorial.po

hibernate 开源框架的代码 jar包希望大家能喜欢

"<![CDATA[.\n"
"+lib\n"
"  <Hibernate and third-party libraries>\n"
"+src\n"
"  +events\n"
"    Event.java\n"
"    Event.hbm.xml\n"
"  +util\n"
"    HibernateUtil.java\n"
"  hibernate.cfg.xml\n"
"+data\n"
"build.xml]]>"
msgstr ""

#. Tag: para
#: tutorial.xml:377
#, no-c-format
msgid ""
"This should again compile without problems. We finally need to configure a "
"logging system - Hibernate uses commons logging and leaves you the choice "
"between Log4j and JDK 1.4 logging. Most developers prefer Log4j: copy "
"<literal>log4j.properties</literal> from the Hibernate distribution (it's in "
"the <literal>etc/</literal> directory) to your <literal>src</literal> "
"directory, next to <literal>hibernate.cfg.xml</literal>. Have a look at the "
"example configuration and change the settings if you like to have more "
"verbose output. By default, only Hibernate startup message are shown on "
"stdout."
msgstr ""
"再次编译这个应用程序应该不会有问题。最后我们需要配置一个日志（logging)系统 "
"－ Hibernate使用通用日志接口，允许你在Log4j和JDK 1.4 日志之间进行选择。多数开"
"发者更喜欢Log4j：从Hibernate的发布包中（它在<literal>etc/</literal>目录下）拷"
"贝<literal>log4j.properties</literal>到你的<literal>src</literal>目录，与"
"<literal>hibernate.cfg.xml</literal>.放在一起。看一下配置示例，如果你希望看到"
"更加详细的输出信息，你可以修改配置。默认情况下，只有Hibernate的启动信息才会显"
"示在标准输出上。"

#. Tag: para
#: tutorial.xml:387
#, no-c-format
msgid ""
"The tutorial infrastructure is complete - and we are ready to do some real "
"work with Hibernate."
msgstr "示例的基本框架完成了 － 现在我们可以用Hibernate来做些真正的工作。"

#. Tag: title
#: tutorial.xml:395
#, no-c-format
msgid "Loading and storing objects"
msgstr "加载并存储对象"

#. Tag: para
#: tutorial.xml:397
#, no-c-format
msgid ""
"Finally, we can use Hibernate to load and store objects. We write an "
"<literal>EventManager</literal> class with a <literal>main()</literal> "
"method:"
msgstr ""
"我们终于可以使用Hibernate来加载和存储对象了，编写一个带有<literal>main()</"
"literal>方法的<literal>EventManager</literal>类："

#. Tag: programlisting
#: tutorial.xml:402
#, no-c-format
msgid ""
"<![CDATA[package events;\n"
"import org.hibernate.Session;\n"
"\n"
"import java.util.Date;\n"
"\n"
"import util.HibernateUtil;\n"
"\n"
"public class EventManager {\n"
"\n"
"    public static void main(String[] args) {\n"
"        EventManager mgr = new EventManager();\n"
"\n"
"        if (args[0].equals(\"store\")) {\n"
"            mgr.createAndStoreEvent(\"My Event\", new Date());\n"
"        }\n"
"\n"
"        HibernateUtil.getSessionFactory().close();\n"
"    }\n"
"\n"
"    private void createAndStoreEvent(String title, Date theDate) {\n"
"\n"
"        Session session = HibernateUtil.getSessionFactory().getCurrentSession"
"();\n"
"\n"
"        session.beginTransaction();\n"
"\n"
"        Event theEvent = new Event();\n"
"        theEvent.setTitle(title);\n"
"        theEvent.setDate(theDate);\n"
"\n"
"        session.save(theEvent);\n"
"\n"
"        session.getTransaction().commit();\n"
"    }\n"
"\n"
"}]]>"
msgstr ""

#. Tag: para
#: tutorial.xml:404
#, no-c-format
msgid ""
"We create a new <literal>Event</literal> object, and hand it over to "
"Hibernate. Hibernate now takes care of the SQL and executes <literal>INSERT</"
"literal>s on the database. Let's have a look at the <literal>Session</"
"literal> and <literal>Transaction</literal>-handling code before we run this."
msgstr ""
"我们创建了个新的<literal>Event</literal>对象并把它传递给Hibernate。现在"
"Hibernate负责与SQL打交道，并把<literal>INSERT</literal>命令传给数据库。在运行"
"之前，让我们看一下处理<literal>Session</literal>和<literal>Transaction</"
"literal>的代码。"

#. Tag: para
#: tutorial.xml:411
#, no-c-format
msgid ""
"A <literal>Session</literal> is a single unit of work. For now we'll keep "
"things simple and assume a one-to-one granularity between a Hibernate "
"<literal>Session</literal> and a database transaction. To shield our code "
"from the actual underlying transaction system (in this case plain JDBC, but "
"it could also run with JTA) we use the <literal>Transaction</literal> API "
"that is available on the Hibernate <literal>Session</literal>."
msgstr ""
"一个<literal>Session</literal>就是个单一的工作单元。我们暂时让事情简单一些，"
"并假设Hibernate<literal>Session</literal>和数据库事务是一一对应的。为了让我们"
"的代码从底层的事务系统中脱离出来（此例中是JDBC，但也可能是JTA），我们使用"
"Hibernate <literal>Session</literal>中的<literal>Transaction</literal> API。"

#. Tag: para
#: tutorial.xml:419
#, no-c-format
msgid ""
"What does <literal>sessionFactory.getCurrentSession()</literal> do? First, "
"you can call it as many times and anywhere you like, once you get hold of "
"your <literal>SessionFactory</literal> (easy thanks to "
"<literal>HibernateUtil</literal>). The <literal>getCurrentSession()</"
"literal> method always returns the \"current\" unit of work. Remember that "
"we switched the configuration option for this mechanism to \"thread\" in "
"<literal>hibernate.cfg.xml</literal>? Hence, the current unit of work is "
"bound to the current Java thread that executes our application. However, "
"this is not the full picture, you also have to consider scope, when a unit "
"of work begins and when it ends."
msgstr ""
"<literal>sessionFactory.getCurrentSession()</literal>是干什么的呢？首先，只要"
"你持有<literal>SessionFactory</literal>（幸亏我们有<literal>HibernateUtil</"
"literal>，可以随时获得），大可在任何时候、任何地点调用这个方法。"
"<literal>getCurrentSession()</literal>方法总会返回“当前的”工作单元。记得我们"
"在<literal>hibernate.cfg.xml</literal>中把这一配置选项调整为\"thread\"了吗？"
"因此，因此，当前工作单元被绑定到当前执行我们应用程序的Java线程。但是，这并非"
"是完全准确的,你还得考虑工作单元的生命周期范围 (scope),它何时开始,又何时结束."

#. Tag: para
#: tutorial.xml:430
#, no-c-format
msgid ""
"A <literal>Session</literal> begins when it is first needed, when the first "
"call to <literal>getCurrentSession()</literal> is made. It is then bound by "
"Hibernate to the current thread. When the transaction ends, either through "
"commit or rollback, Hibernate automatically unbinds the <literal>Session</"
"literal> from the thread and closes it for you. If you call "
"<literal>getCurrentSession()</literal> again, you get a new "
"<literal>Session</literal> and can start a new unit of work. This "
"<emphasis>thread-bound</emphasis> programming model is the most popular way "
"of using Hibernate, as it allows flexible layering of your code (transaction "
"demarcation code can be separated from data access code, we'll do this later "
"in this tutorial)."
msgstr ""
"<literal>Session</literal>在第一次被使用的时候,即第一次调用"
"<literal>getCurrentSession()</literal>的时候,其生命周期就开始。然后它被"
"Hibernate绑定到当前线程。当事务结束的时候，不管是提交还是回滚，Hibernate会自"
"动把<literal>Session</literal>从当前线程剥离，并且关闭它。假若你再次调用"
"<literal>getCurrentSession()</literal>，你会得到一个新的<literal>Session</"
"literal>，并且开始一个新的工作单元。这种<emphasis>线程绑定(thread-bound)</"
"emphasis>的编程模型（model）是使用Hibernate的最广泛的方式,因为它支持对你的代"
"码灵活分层(事务划分可以和你的数据访问代码分离开来,在本教程的后面部分就会这么"
"做)。"

#. Tag: para
#: tutorial.xml:441
#, no-c-format
msgid ""
"Related to the unit of work scope, should the Hibernate <literal>Session</"
"literal> be used to execute one or several database operations? The above "
"example uses one <literal>Session</literal> for one operation. This is pure "
"coincidence, the example is just not complex enough to show any other "
"approach. The scope of a Hibernate <literal>Session</literal> is flexible "
"but you should never design your application to use a new Hibernate "
"<literal>Session</literal> for <emphasis>every</emphasis> database "
"operation. So even if you see it a few more times in the following (very "
"trivial) examples, consider <emphasis>session-per-operation</emphasis> an "
"anti-pattern. A real (web) application is shown later in this tutorial."
msgstr ""
"和工作单元的生命周期这个话题相关，Hibernate <literal>Session</literal>是否被"
"应该用来执行多次数据库操作？上面的例子对每一次操作使用了一个"
"<literal>Session</literal>，这完全是巧合，这个例子不是很复杂，无法展示其他方"
"式。Hibernate <literal>Session</literal>的生命周期可以很灵活，但是你绝不要把"
"你的应用程序设计成为<emphasis>每一次</emphasis>数据库操作都用一个新的"
"Hibernate <literal>Session</literal>。因此就算下面的例子（它们都很简单）中你"
"可以看到这种用法，记住<emphasis>每次操作一个session</emphasis>是一个反模式。"
"在本教程的后面会展示一个真正的(web)程序。"

#. Tag: para
#: tutorial.xml:452
#, no-c-format
msgid ""
"Have a look at <xref linkend=\"transactions\"/> for more information about "
"transaction handling and demarcation. We also skipped any error handling and "
"rollback in the previous example."
msgstr ""
"关于事务处理及事务边界界定的详细信息，请参看<xref linkend=\"transactions\"/"
">。在上面的例子中，我们也忽略了所有的错误与回滚的处理。"

#. Tag: para
#: tutorial.xml:458
#, no-c-format
msgid ""
"To run this first routine we have to add a callable target to the Ant build "
"file:"
msgstr ""
"为第一次运行我们的程序，我们得在Ant的build文件中增加一个可以调用得到的"
"target。"

#. Tag: programlisting
#: tutorial.xml:462
#, no-c-format
msgid ""
"<![CDATA[<target name=\"run\" depends=\"compile\">\n"
"    <java fork=\"true\" classname=\"events.EventManager\" classpathref="
"\"libraries\">\n"
"        <classpath path=\"${targetdir}\"/>\n"
"        <arg value=\"${action}\"/>\n"
"    </java>\n"
"</target>]]>"
msgstr ""

#. Tag: para
#: tutorial.xml:464
#, no-c-format
msgid ""
"The value of the <literal>action</literal> argument is set on the command "
"line when calling the target:"
msgstr ""
"<literal>action</literal>参数（argument）的值是通过命令行调用这个target的时候"
"设置的："

#. Tag: programlisting
#: tutorial.xml:469
#, no-c-format
msgid "<![CDATA[C:\\hibernateTutorial\\>ant run -Daction=store]]>"
msgstr ""

#. Tag: para
#: tutorial.xml:471
#, no-c-format
msgid ""
"You should see, after compilation, Hibernate starting up and, depending on "
"your configuration, lots of log output. At the end you will find the "
"following line:"
msgstr ""
"你应该会看到，编译以后，Hibernate根据你的配置启动，并产生一大堆的输出日志。在"
"日志最后你会看到下面这行："

#. Tag: programlisting
#: tutorial.xml:476
#, no-c-format
msgid ""
"<![CDATA[[java] Hibernate: insert into EVENTS (EVENT_DATE, title, EVENT_ID) "
"values (?, ?, ?)]]>"
msgstr ""

#. Tag: para
#: tutorial.xml:478
#, no-c-format
msgid ""
"This is the <literal>INSERT</literal> executed by Hibernate, the question "
"marks represent JDBC bind parameters. To see the values bound as arguments, "
"or to reduce the verbosity of the log, check your <literal>log4j.properties</"
"literal>."
msgstr ""
"这是Hibernate执行的<literal>INSERT</literal>命令，问号代表JDBC的绑定参数。如"
"果想要看到绑定参数的值或者减少日志的长度，就要调整你在<literal>log4j."
"properties</literal>文件里的设置。"

#. Tag: para
#: tutorial.xml:484
#, no-c-format
msgid ""
"Now we'd like to list stored events as well, so we add an option to the main "
"method:"
msgstr ""
"我们想要列出所有已经被存储的events，就要增加一个条件分支选项到main方法中去。"

#. Tag: programlisting
#: tutorial.xml:488
#, no-c-format
msgid ""
"<![CDATA[if (args[0].equals(\"store\")) {\n"
"    mgr.createAndStoreEvent(\"My Event\", new Date());\n"
"}\n"
"else if (args[0].equals(\"list\")) {\n"
"    List events = mgr.listEvents();\n"
"    for (int i = 0; i < events.size(); i++) {\n"
"        Event theEvent = (Event) events.get(i);\n"
"        System.out.println(\"Event: \" + theEvent.getTitle() +\n"
"                           \" Time: \" + theEvent.getDate());\n"
"    }\n"
"}]]>"
msgstr ""

#. Tag: para
#: tutorial.xml:490
#, no-c-format
msgid "We also add a new <literal>listEvents() method</literal>:"
msgstr "我们也增加一个新的<literal>listEvents()</literal>方法:"